In the field of phlebotomy, tubes, such as those partially evacuated for automatic blood intake, are used to receive blood from a needle. Kits of such tubes are often provided, for example, as shown in U.S. Pat. No. 3,405,706, FIG. 7. However, the tubes shown in the '706 patent all have the same volume. It is conventional to provide tubes of differing volume, since in some instances much less blood is needed, e.g., for pediatrics. For a large volume tube, the small contained blood volumes are difficult to remove after collection due to the large surface area. Prior to this invention, such tubes of differing volume have also necessitated different exterior sizes, e.g., the smaller volume tubes have also been shorter and/or narrower than the larger volume tubes.
Such difference in overall size as well as volume is advantageous in identifying (by shape) which tube is for what volume. However, it has a substantial disadvantage. In use, the tubes are inserted into a phlebotomy syringe, and in most instances the syringe is designed to receive a tube having a predetermined fixed length and diameter. For example, the phlebotomy tube shown in U.S. Pat. No. 4,813,426 snugly fits the diameter of the syringe which holds it. That syringe will not accommodate a tube of larger diameter, and only awkwardly will receive one of smaller diameter due to the sloppy fit that ensues. The sloppy fit that occurs in such a case is particularly disadvantageous when drawing blood from a child who may be very active and who may disturb the loose-fitting tube.
Hence, differently-sized collection tubes normally necessitate differently-sized syringes, which in turn leads to added expense and procedures.
Therefore, prior to this invention, there has been a need for a kit of universally sized blood collection tubes to be used in a phlebotomy syringe, that will allow differing volumes to be collected in such tubes, all with the same single phlebotomy syringe.